Topographic mapping of Mangawhai sand spit and development of a draft framework for monitoring future changes
- Author
- Dickson M, Ford M, Ryan E
- Year
- 2024
- Journal / Source
- Report for Mangawhai Matters Inc and Mangawhai Harbour Restoration Society
- Publisher / Organisation
- University of Auckland
- Summary
- A survey of the topography of Mangawhai Spit was conducted in 2024 using a dronebased LiDAR system, which allowed for a comparison of topographic changes with data from an earlier aircraft-based LiDAR survey conducted in 2018. A web-platform is provided to visualize digital elevation models (DEMs) as well as historic photographs and digitised coastlines, which provide an overview of historic changes to Mangawhai Spit. Water levels were calculated for extreme events, including the future effects of sea level rise (SLR). This enabled maps to be drawn identifying potential points for breakthroughs by the sea and flow paths through which water might penetrate the spit leading to potential flooding from the sea. The information provides baseline data against which to monitor future change. The report concludes with guidance and options for monitoring future change.